The race to the South Pole involving Prince Harry and his fellow Walking With The Wounded expedition competitors has been suspended for safety reasons.

Harry had started off on the gruelling charity trek with a team of injured British servicemen and women against groups from the US and the Commonwealth in an expedition organised by the charity Walking With The Wounded.

Ed Parker, the expedition director, has taken the decision to suspend the race to the pole, but is determined that all the members will make it to the South Pole as one group.

On the charity website, he said: "We have had a tricky couple of days. The weather remains good but the terrain is very difficult, far harder than we were anticipating and because of various factors, I have decided to suspend the race.

"The reasons for this are entirely safety based. I am looking at the three teams. They are going really well but people are beginning to get very, very tired.

"With our doctor here, who I am in constant contact with, we just feel we are beginning to push people a little too hard, so I have suspended the race."

The charity's website said this is "certainly not the end" for the challenge, but added that steps have been put into place to ensure that all of those involved are kept safe.

The team members are determined to prove their strength and courage but this must be done without jeopardising anyone's well-being, the charity said.

The final leg of the challenge will begin from the team's second allotted checkpoint, 112 km (70 miles) from the South Pole.

The team will be driven to this point and, over the course of the next seven days, will move as one whole allied team to reach the South Pole together.

A post on the charity's website said: "On Day 5 of the Virgin Money South Pole Allied Challenge, as the teams arrived at their first checkpoint, it became obvious that underneath the concrete determination of all the team members, the harsh reality of the Antarctic was starting to take its toll."

Mr Parker, co-founder of Walking With The Wounded, said: "This does not mean that the expedition is over. Far from it. We came down here, determined to get 12 men and women, all injured in conflict, to the South Pole, and so we will."

He added: "Tomorrow we start the last leg, 112 km, to the Pole, with no stress being placed on the teams, and with the new race format enabling them all to do this in their own time.

"Each evening, the expedition will be camping together, all able to enjoy and share each other's experiences. By Friday or Saturday next week, I strongly believe that every member of the expedition will be standing on the South Pole, celebrating what will have been the most extraordinary shared journey.

"We feel your support every step of the way, please continue to follow us and support the walk."

In total, 12 injured service personnel who have overcome life-changing injuries are taking part. They have tackled challenging training programmes to prepare themselves for the conditions in Antarctica.

Trekking around 15km to 20km (nine to 12 miles) a day, the teams were preparing to endure temperatures as low as minus 45C and 50mph winds as they pull their 70kg sleds, known as pulks, towards the southernmost point on the globe.

Harry took part in some of a Walking With The Wounded expedition to the North Pole in 2011.

Harry has previously spoken of the Prince of Wales' concerns about the expedition and voiced his frustrations at the bad weather delaying preparations.

He said: ''My father was a little bit concerned, I obviously tried to keep him calm by saying the North Pole was the dangerous one because we were walking on frozen ocean, whereas this time, yes, there's crevasses - but hopefully the guys will take us around that.

''Apart from frostbite and stuff like that you should be able to look after yourself.''

Harry's team-mate on UK Team Glenfiddich, Guy Disney, said: "The first four days was a full-out slog. It really tested every single individual mentally and physically.

"I think everyone, including myself, has managed to get a hell of a lot out of it and it will be an experience that will live with us for the rest of our lives.

"However, due to a few small injuries - nothing too serious - and the weather, it is really putting us behind and so the race element has been stopped, but for very good reasons."

He added: "We still have another seven days of walking, which should be great fun, and without the race element it means we can really focus on what the expedition set out to achieve.

"All is well, morale is good, everyone is rested, fit and ready to go. Another seven days to push. We will probably make about 15-16km each day.

"We are about 112km from the South Pole and we all can't wait to get there as one big group.

"There is a bigger goal here, which we all set out from the start, and that is what we need to achieve. All is well."